(1) Field of the Invention
The present invention relates to a novel compound having a photochromic action, a composition comprising this compound, and a use thereof. More particularly, the present invention relates to a novel compound which is colored from the colorless state under irradiation of an ultraviolet ray-containing light such as sunlight or a light of a mercury lamp, this change is reversible and the color fading speed is high, a composition comprising this novel compound and a use thereof.
(2) Description of the Related Art
The photochromism is the phenomenon which has attracted attention in these several years, and this phenomenon is a reversible phenomenon in which when a certain compound is irradiated with an ultraviolet ray-containing light such as sunlight or a light of a mercury lamp, the color of the compound is promptly changed and when the irradiation is stopped and the compound is placed in the dark place, the original color is manifested again. The compound having this property is called "photochromic compound", and various photochromic compounds have been synthesized. However, a special common structure is not found among these compounds.
The specification of Japanese Unexamined Patent publication No. 63-30487 discloses spiroxazine compounds represented by the following formula: ##STR2##
The compounds show photochromic characteristics in a solution or a polymer matrix. However, although the photochromic characteristics of the spiroxazine compounds is remarkable at temperatures not higher than 20.degree. C., it is not excellent at temperatures close to the ambient temperature (20.degree. to 30.degree. C.), particularly higher than the ambient temperature.
Therefore, these compounds can not be used for a photochromic lens at relatively warm areas.